JPS6222376A - Thin lithium battery - Google Patents

Abstract

PURPOSE:To prevent any liquid leakage from a thin lithium battery so as to increase its reliability by sufficiently sealing the battery by using an electrolyte which is composed of a lithium salt, a polymer containing a lactone structure and a nonaqueous solvent. CONSTITUTION:After a dimethoxyethane addition product of LiBphi4 is dissolved in propylene carbonate, poly(3-vinyl-1,4-butyrolactone) is mixed into the solution to seal this compound in the solution and then the resulting mixture is heated to prepare a homogeneous viscous electrolyte. Next, a mixture consisting of this electrolyte and TiS powder in a ratio by volume of 30:70 is kneaded and then the kneaded mixture is applied to the entire surface of a positive current collector plate to make a positive electrode. Next, a separator consisting of a porous polypropylene is formed on the positive electrode and a negative electrode made of a lithium-aluminum alloy is placed on the separator. After that, a negative current collector plate is placed over the negative electrode and then fused to it, thereby producing a thin lithium battery with a total thickness of 0.5mm.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、リチウムまたはリチウム合金を負極とじ、
正負両極集電板の対向する平坦状の周辺部で接着封止さ
れた構造を有する薄型のリーチラム電池に関す、る。　
　・ ［従来の技術］ 従来より汎用されるボタン型やコイン型などのリチウム
電池は、一般に、正極活物質および結合剤を含む正極と
リチウムまたはリチウム合金からなる負極との間にセパ
レータを介在させ、これらを缶体をなす正極集電板と負
極集電板との間に配置すると共に、リチウム塩を非水系
溶媒に溶解した高流動性の液体である電解質をセパレー
タおよび正極に浸潤させた上で、正極集電板の立ち上が
り周縁部をバッキング材を挾んでかしめ屈曲して封止し
た構造を有している（文献不詳）。[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for forming a negative electrode using lithium or a lithium alloy.
The present invention relates to a thin Leechlam battery having a structure in which positive and negative current collector plates are adhesively sealed at opposing flat peripheral parts.
・ [Conventional technology] Conventionally used button-type and coin-type lithium batteries generally have a separator interposed between a positive electrode containing a positive electrode active material and a binder and a negative electrode made of lithium or a lithium alloy. These are placed between a positive electrode current collector plate and a negative electrode current collector plate forming a can, and an electrolyte, which is a highly fluid liquid made by dissolving lithium salt in a non-aqueous solvent, is infiltrated into the separator and the positive electrode. , it has a structure in which the rising peripheral edge of the positive electrode current collector plate is sealed by sandwiching a backing material and caulking and bending it (document unknown).

しかしながら、近年における電子機器類の小型化、軽量
化、薄型化などに伴って、これに使用するリチウム電池
としてもカード型やフレキシブル型などのたとえば総厚
が０．５開型度という非常に薄型で高性能なものが要−
望されている。このような薄型電池になると、前記した
ボタン型やコイン型の電池における封止手段では構造上
および加工技術上の制約から電池総厚１．Ｏｗ程度が限
界であるため、正負両極集電板の平坦状とした対向する
周縁部で接着剤を介して封止する方式を採用せざるを得
ない（文献不詳）。However, as electronic devices have become smaller, lighter, and thinner in recent years, the lithium batteries used in these devices have become very thin, such as card-type or flexible types, with a total thickness of 0.5 degree. I need something with high performance.
desired. When it comes to such thin batteries, the sealing means for the button-type or coin-type batteries described above has a total battery thickness of 1.5 mm due to structural and processing technology constraints. Since Ow is the limit, it is necessary to adopt a method of sealing the flat opposing peripheral edges of the positive and negative current collector plates with an adhesive (unspecified literature).

［発明が解決しようとする問題点］ しかるに、このような薄型電池の電解質として前記した
従来の液体電解質を使用した場合、両極集電板が薄型化
のためにほぼ平板状となることから、電池組立時に電解
質が外部へ流出しやすく、その必要量を確保しにくく、
かつ両極集電板の周辺部の濡れによって封止が非常に困
難になる。また、組立後の薄型電池は、使用中に幅の狭
い封止部に常に液体電解質が接触するために漏液を生じ
やすく、信頼性に難があり、さらに二次電池とした場合
では充放電の繰り返しによって負極リチウムがデンドラ
イト状（樹枝状）に析出して短絡を発生しやすく、寿命
が短くなるという問題点があった。[Problems to be Solved by the Invention] However, when the above-mentioned conventional liquid electrolyte is used as the electrolyte for such a thin battery, since the bipolar current collector plate becomes almost flat due to the thinning, the battery Electrolyte tends to leak out during assembly, making it difficult to secure the required amount.
In addition, sealing becomes extremely difficult due to wetting of the periphery of the bipolar current collector plates. In addition, after assembly, thin batteries tend to leak because the liquid electrolyte constantly comes into contact with the narrow sealing part during use, making reliability difficult. Furthermore, when used as a secondary battery, charging and discharging By repeating this process, the negative electrode lithium precipitates in a dendrite shape, which tends to cause short circuits, resulting in a shortened lifespan.

一方、このような薄型電池の封止をホットメルト型接着
剤などの熱融着性材料による熱融着にて行う場合、該材
料として予め幅や厚みを適当に設定した環状シート形態
のものを使用できるので、一般的な塗料溶液型の接着剤
におけるような塗布操作が不要でかつ電池内部への流入
の惧れもないという利点がある。ところが、この場合に
従来の液体電解質では、融着時の加熱にて蒸気圧が高ま
り、液が飛散して封止自体を困難にするという問題があ
った。On the other hand, when sealing such a thin battery by heat fusion using a heat-adhesive material such as a hot-melt adhesive, the material is in the form of an annular sheet with an appropriate width and thickness set in advance. Since it can be used, it has the advantage that it does not require a coating operation unlike a general paint solution type adhesive and there is no fear of it flowing into the inside of the battery. However, in this case, conventional liquid electrolytes have a problem in that the vapor pressure increases during heating during fusion, causing the liquid to scatter, making sealing itself difficult.

なお、特殊なものとして固体電解質を用いた電池も提案
されており、薄型電池においても固体電解質を用いるこ
とが考えられるが、このよう・な固体電解質は液体電解
質に比較してイオン伝導度が著しく低いために電池性能
が劣り、かつ製造プロセスが複雑でコスト高になるなど
の欠点がある。Note that special batteries using solid electrolytes have also been proposed, and solid electrolytes may also be used in thin batteries, but such solid electrolytes have significantly lower ionic conductivity than liquid electrolytes. There are drawbacks such as poor battery performance due to low battery life, and a complicated manufacturing process that increases costs.

Ｅ問題点を解決するための手段］ この発明者らは、上記問題点を解決するために鋭意検討
を重ねた結果、電解質として特定の成分を使用した粘性
体を用いた場合、電池組立時に従来の液体電解質のよう
に外部へ流出する惧れがなく、その必要量を確保できる
と共に接着剤による封止が支障なく行え、また電解質は
塗り付けによって添加できることから添加操作も容易で
あり、しかも熱融着性材料の熱抛着による封止方式を採
用しても電解質の飛散を生じず充分な封止が可能となり
、加えて漏液を生じにくく信頼性が高く二次電池として
も高寿命である薄型リチウム電池が得られることを知り
、この発明をなすに至った。Means for Solving Problem E] As a result of intensive studies to solve the above problem, the inventors found that when a viscous material containing a specific component is used as an electrolyte, it is difficult to assemble a battery using conventional methods. Unlike liquid electrolyte, there is no risk of it leaking outside, the required amount can be secured, sealing with adhesive can be performed without any problem, and since the electrolyte can be added by smearing, the addition operation is easy, and it does not require heat treatment. Even if a sealing method using thermal adhesion of a fusible material is used, sufficient sealing is possible without causing electrolyte scattering.In addition, it is resistant to leakage and is highly reliable and has a long life as a secondary battery. After learning that a certain thin lithium battery could be obtained, he came up with this invention.

すなわち、この発明は、正極集電板と負極集電板との間
に正極とリチウムまたはリチウム合金からなる負極と両
極間に介在するセパレータとを含む電池要素が配置され
、上記両極集電板の対向する平坦状の周辺部で接着封止
された構造の薄型リチウム電池において、電解質として
、リチウム塩と、分子内にラクトン構造を有するポリマ
ーと、これら両者を溶解する非水系溶媒とが含まれてな
る粘性体が使用されていることを特徴とする薄型リチウ
ム電池に係る。That is, in the present invention, a battery element including a positive electrode, a negative electrode made of lithium or a lithium alloy, and a separator interposed between the two electrodes is arranged between a positive electrode current collector plate and a negative electrode current collector plate, and In a thin lithium battery having a structure in which opposing flat peripheral parts are adhesively sealed, the electrolyte contains a lithium salt, a polymer having a lactone structure in the molecule, and a non-aqueous solvent that dissolves both. The present invention relates to a thin lithium battery characterized in that a viscous material is used.

〔発明の構成・作用〕[Structure and operation of the invention]

この発明において使用する電解質は、既述のようにリチ
ウム塩と分子内にラクトン構造を有するポリマーとこれ
ら゛両者を溶解する非水系溶媒とからなるものであり、
上記ポリマーと非水系溶媒とがゲル化して増粘作用を果
たす結果、全体が上記ポリマーを含まない通常の液体電
解質のような高流動性を示さず、塗り付は可能でかつ熱
融着による封止時の加熱によっても飛散しない粘性体と
なったものである。As mentioned above, the electrolyte used in this invention is composed of a lithium salt, a polymer having a lactone structure in its molecule, and a non-aqueous solvent that dissolves both.
As a result of the above-mentioned polymer and non-aqueous solvent gelling and exerting a thickening effect, the whole does not exhibit high fluidity like ordinary liquid electrolytes that do not contain the above-mentioned polymer, and can be applied and sealed by heat fusion. It is a viscous material that does not scatter even when heated when stopped.

なお、このように電解質にゲル化による増粘作用をもた
らすものは上記ポリマー以外にも種々考えられるが、リ
チウム電池の電解質に使用する非水系溶媒として電極材
料に対し化学的に安定である必要から一般的にγ−ブチ
ロラクトンやプロピレンカーボネートなどの−ＣＯ−Ｏ
−結合を有する高沸点溶媒が用いられるため、これら溶
媒と類似した極性を示すラクトン構造を分子内に有する
上記ポリマーによればとくにゲル化しやすいという利点
がある。In addition to the above-mentioned polymers, there are various other substances that can give the electrolyte a thickening effect due to gelation, but as a non-aqueous solvent used in the electrolyte of lithium batteries, it is necessary to be chemically stable with respect to the electrode material. Generally -CO-O such as γ-butyrolactone and propylene carbonate
Since a high boiling point solvent having a - bond is used, the above-mentioned polymer having a lactone structure in its molecule having a polarity similar to that of these solvents has the advantage of being particularly easy to gel.

このようなポリマーとしては、ラクトン構造が側鎖中に
存在するものと主鎖中に存在するもののいずれをも使用
可能であるが、製造および入手の容易さの面から通常は
前者のラクトン構造が側鎖中に存在するポリマーが用い
られる。またこれらポリマーは、重合度によって固体、
半固体、液体と種々の形態があるが、非水系溶媒に溶解
してゲル化による増粘作用を示すものであればいずれも
使用可能である。なお、これらポリマーのラクトン構造
は、環状構造中に−ＣＯ−Ｏ−を含むものであればよく
、環を構成する原子数はとくに限定されないが、たとえ
ばプロピオラクトン（β−ラクトン）構造、ブチロラク
トン（γ−ラクトン）構造、δ−バレロラクトン（δ−
ラクトン）構造などの６員環以下のものが好適である。As such polymers, both those in which the lactone structure exists in the side chain and those in the main chain can be used, but the former lactone structure is usually used from the viewpoint of ease of production and availability. Polymers present in side chains are used. Also, these polymers can be solid or solid depending on the degree of polymerization.
There are various forms such as semi-solid and liquid, but any form can be used as long as it dissolves in a non-aqueous solvent and exhibits a thickening effect due to gelation. The lactone structure of these polymers may have -CO-O- in the cyclic structure, and the number of atoms constituting the ring is not particularly limited. For example, propiolactone (β-lactone) structure, butyrolactone structure, etc. (γ-lactone) structure, δ-valerolactone (δ-
A 6-membered ring or less, such as a lactone) structure, is preferred.

上記のラクトン構造が側鎖中に存在するポリマーの代表
例としては、分子内にビニル基を有するラクトンの単独
重合体、ならびに上記ラクトンとこれに共重合可能な他
のモノマーとの共重合体が挙げられ、これらの平均分子
量はｓ、ｏｏｏ〜１００゜０００程度のものが好適であ
る。そして上記の分子内にビ三ル基を含むラクトンとし
ては、環を構成する原子数およびビニル基の結合位置が
種々異なるものを使用できるカミとくに好ましい例とし
て３−ビニル−１・４−ブチロラクトンおよび４−ビニ
ル−１・４−ブチロラクトンがある。Typical examples of polymers in which the above-mentioned lactone structure exists in the side chain include homopolymers of lactones having a vinyl group in the molecule, and copolymers of the above-mentioned lactones with other monomers that can be copolymerized with them. The average molecular weight of these is preferably about s, ooo to 100°,000. As the above-mentioned lactone containing a vinyl group in the molecule, lactones having various numbers of atoms constituting the ring and bonding positions of the vinyl group can be used. Particularly preferable examples include 3-vinyl-1,4-butyrolactone and There is 4-vinyl-1,4-butyrolactone.

また上記共重合体に使用される共重合可能な他のモノマ
ーとしては、とくに限定されないが、前記のゲル化によ
る増粘作用をもたらす効果の大きいものとして（メタ）
アクリロニトリルおよびメタクリル酸アルキルエステル
が挙げられる。そして上記メタクリル酸アルキルエステ
ルとしてはとくにアルキル基の炭素数が１〜４程度のも
のが好適である。なお、このような共重合体における分
子内にビニル基を有するラクトンモノマーの使用比率は
該ラクトンモノマーがモノマー全体の３０モル％以上と
なる範囲がよく、この比率が少ないとラクトン構造によ
る既述利点が充分に発揮されなくなる。In addition, other copolymerizable monomers used in the above copolymer are not particularly limited;
Acrylonitrile and methacrylic acid alkyl esters are mentioned. As the above-mentioned methacrylic acid alkyl ester, those in which the alkyl group has about 1 to 4 carbon atoms are particularly suitable. In addition, the ratio of the lactone monomer having a vinyl group in the molecule in such a copolymer is preferably such that the lactone monomer accounts for 30 mol% or more of the total monomer, and if this ratio is small, the above-mentioned advantages due to the lactone structure are reduced. is not fully demonstrated.

以上の如き分子内にラクトン構造を有するポリマーの使
用量は、電解質全体の４〜４０重量％を占める量、とく
に好ましくは４〜３０重量％を占める量とするのがよい
。この使用量が多すぎるとイオン伝導度および正極利用
率の低下が無視できなくなると共に電解質の粘稠性が強
くなりすぎて塗り付けなどの操作性が悪くなり、逆に該
使用量が少なすぎると流動性が大きくなって既述した従
来の液体電解質と同様の問題を生じる。The amount of the polymer having a lactone structure in its molecule as described above is preferably 4 to 40% by weight, particularly preferably 4 to 30% by weight of the entire electrolyte. If the amount used is too large, the decrease in ionic conductivity and positive electrode utilization rate cannot be ignored, and the viscosity of the electrolyte becomes too strong, resulting in poor operability such as painting.On the other hand, if the amount used is too small, The increased fluidity causes problems similar to those of the conventional liquid electrolyte described above.

この発明において電解質に使用するリチウム塩としては
、従来よりリチウム電池用電解質成分として知られる種
々のものを使用可能であるが、とくに好適なものとして
ＬＩＢＩｌ１４（φはフェニル基を意味する）、ＬｉＰ
Ｆ６、ＬｉＣＦ３ＳＯ３、Ｌ　１ＡｓＦ６、ＬｉＢＦ、
などが挙げられ、これらは予め非水系溶媒の付加物とし
た形態でも使用でき、２種以上を併用してもよい。なお
、従来より電解質成分として知られるＬｉＣ１’０４は
取扱い上で危険性が大きいため、好ましくない。またこ
のようなリチウム塩の濃度は０．３〜３ｍｏｌ／ｌが好
ましく、とくに好ましくは０．５〜１ｍｏｌ／Ｖとする
のがよい。As the lithium salt used in the electrolyte in this invention, various salts conventionally known as electrolyte components for lithium batteries can be used, but particularly preferred ones include LIBII14 (φ means a phenyl group), LiP
F6, LiCF3SO3, L1AsF6, LiBF,
These can also be used in the form of adducts of non-aqueous solvents, or two or more types can be used in combination. Note that LiC1'04, which has been conventionally known as an electrolyte component, is not preferred because it is dangerous in handling. The concentration of such a lithium salt is preferably 0.3 to 3 mol/l, particularly preferably 0.5 to 1 mol/V.

非水系溶媒としては、リチウム塩と反応せず、このリチ
ウム塩および前記ポリマーの両者を溶解でき、かつ前記
ポリマーと混合してゲル化する性質を有するものであれ
ばよく、従来よりリチウム電池の電解質用として既知の
ものを種々使用できるが、とくに好適なものとしてプロ
ピレンカーボネート、γ−ブチロラクトン、ジメトキシ
エタン、ジオキソランの４種が挙げられ、これらは２種
以上を併用しても差し支えない。The non-aqueous solvent may be any non-aqueous solvent as long as it does not react with the lithium salt, can dissolve both the lithium salt and the polymer, and has the property of gelling when mixed with the polymer. Although various known materials can be used, particularly preferred are propylene carbonate, γ-butyrolactone, dimethoxyethane, and dioxolane, and two or more of these may be used in combination.

なお、この発明で使用する電解質の粘性体として、上述
した３成分の好適な組合せは多数存在するが、電池特性
および電解質の均一性の面でリチウム塩がＬｉＢφ４の
ジメトキシエタン付加物で非水系溶媒がγ−ブチロラク
トンまたはプロピレンカーボネートである場合に最も良
好な結果が得られている。There are many suitable combinations of the above-mentioned three components as the viscous electrolyte used in this invention, but from the viewpoint of battery characteristics and electrolyte uniformity, it is preferable that the lithium salt is a dimethoxyethane adduct of LiBφ4 and a non-aqueous solvent. Best results have been obtained when is γ-butyrolactone or propylene carbonate.

第１図はこの発明に係るリチウム電池の一例を示すもの
である。図において１はステンレス鋼からなる方形平板
状の正極集電板、２は周辺を一面側へ段状に折曲して主
面と同じ向きの平坦状の周辺部２ａを設けたステンレス
鋼からなる浅い方形皿状の負極集電板、３は両極集電板
１，２°の対向する周辺部１ａ、２ａ間を封止した接着
剤層、４は両極集電板１，２間に構成される空間５内に
おいて正極集電板１側に配された正極、６は空間５内に
おいて負極集電板２側に装填されたリチウムまたはリチ
ウム合金からなる負極、７は両極４，６間に介在させた
多孔性ポリプロピレンなどの多孔性材料からなるセパレ
ータ、８は正極４を取囲むように配設されたポリプロピ
レンなどからなる方形環状の枠体である。FIG. 1 shows an example of a lithium battery according to the present invention. In the figure, 1 is a rectangular flat positive electrode current collector plate made of stainless steel, and 2 is made of stainless steel whose periphery is bent stepwise toward one side to provide a flat periphery 2a in the same direction as the main surface. A shallow rectangular dish-shaped negative electrode current collector plate, 3 is an adhesive layer that seals between the opposing peripheral parts 1a and 2a of the two electrode current collector plates 1 and 2 degrees, and 4 is a layer formed between the two electrode current collector plates 1 and 2; a positive electrode arranged on the positive electrode current collector plate 1 side in the space 5; 6 a negative electrode made of lithium or a lithium alloy loaded on the negative electrode current collector plate 2 side in the space 5; 7 interposed between the two electrodes 4 and 6; The separator 8 is made of a porous material such as porous polypropylene, and is a rectangular ring-shaped frame made of polypropylene or the like, which is disposed so as to surround the positive electrode 4 .

この場合、前述した電解質は通常では組込み前のセパレ
ータ７に予め塗布して含浸させることにより、電池内部
に添加される。このとき電解質が粘性体であるため、組
立て基面に多少の傾斜があったり、振動が加わっても周
辺へ流出することがなく、塗り付は位置から組込み位置
へのセパレータ７の運搬時にも滴下する惧れはなく、か
つ添加量を広範に調整することが可能である。In this case, the above-mentioned electrolyte is usually added to the inside of the battery by coating and impregnating the separator 7 in advance before assembly. At this time, since the electrolyte is a viscous substance, it will not flow out to the surrounding area even if the assembly base is slightly inclined or vibration is applied, and the coating will not drip even when the separator 7 is transported from the installation position to the installation position. There is no risk that this will occur, and the amount added can be adjusted over a wide range.

一方、接着剤層３．とじては、一般的な塗料溶液型の接
着剤も使用できるが、とくに熱融着性材料からなるもの
が好適である。このような熱融着性材料としては、熱融
着前の形態が両極集電板１，２の周辺部１ａ、２ａの幅
に対応する幅に予め設定した環状などの成形シートであ
るものを使用できる。On the other hand, adhesive layer 3. Although general paint solution type adhesives can be used for closing, adhesives made of heat-fusible materials are particularly suitable. Such heat-sealable materials include those whose form before heat-sealing is a molded sheet, such as a ring, whose width is preset to correspond to the width of the peripheral parts 1a and 2a of the bipolar current collector plates 1 and 2. Can be used.

すなわち、封止操作は上記両層辺部１ａ、２ａ間に上記
成形シートを挾んで圧接し、この状態で側周辺部１ａ　
、２ａ　部分を所定温度まで加熱すればよい。That is, in the sealing operation, the molded sheet is sandwiched and pressed between the side portions 1a and 2a of both layers, and in this state, the side peripheral portion 1a is
, 2a may be heated to a predetermined temperature.

そして、この加熱過程においては電解質が粘性体である
ために従来の液体のように飛散することがなく、容易に
確実な封止が達成される。また上述のように熱融着前の
形態が固形の成形物であることから、取扱い操作および
組付は操作が非常に容易であると共に、塗料溶液型接着
剤を用いる場合のように空間５内へ流入して電解質と混
じり合う川れがない。In this heating process, since the electrolyte is a viscous substance, it does not scatter unlike conventional liquids, and reliable sealing can be easily achieved. Furthermore, as mentioned above, since the form before heat fusion is a solid molded product, handling and assembly are very easy, and the space 5 can be easily handled and assembled, unlike when using a paint solution type adhesive. There are no rivers flowing into the water and mixing with electrolytes.

なお、このような熱融着性材料にはホットメルト型接着
剤、ハーメチックシール可能なセラミックを始め、種々
のものを使用できる。Note that various types of heat-fusible materials can be used, including hot-melt adhesives and hermetically sealable ceramics.

また、正極４としては、活物質とテフロン粉末などの結
合剤と必要に応じてカルボニルニッケルなどの電子伝導
助剤とを混、合してシート状に成形したものを使用して
もよいが、前述した電解質の粘性体を活物質と必要に応
じて導電助剤に混練して粘稠物きしたものを好適に使用
できる。すなわち、後者の粘稠物はスクリーン印刷など
によって正極集電板１上に塗布形成できるため、前者の
ような成形工程が不要となり、形成操作も極めて簡単で
低コスト化が図れると共に、薄層化が容易であることか
ら薄型電池への適用性に優れる。Further, as the positive electrode 4, a sheet formed by mixing an active material, a binder such as Teflon powder, and, if necessary, an electron conduction aid such as carbonyl nickel, may be used. A viscous substance obtained by kneading the above-mentioned viscous electrolyte with an active material and, if necessary, a conductive agent to form a viscous substance, can be suitably used. In other words, the latter viscous material can be applied and formed on the positive electrode current collector plate 1 by screen printing, etc., so the forming process like the former is not necessary, and the forming operation is extremely simple, reducing costs and making the layer thinner. Since it is easy to use, it has excellent applicability to thin batteries.

そして枠体８は正極４として上記粘稠物を使用する場合
にその塗布量を設定する機能を持つものである。すなわ
ち、予めこの枠体８を正極集電板１上に載置しておき、
その内側に一杯に上記粘稠物を塗布充填することによっ
て塗布量が一定になるから、所望の塗布量に応じて枠体
８の厚さと大きさつまり包囲面積を定めればよい。The frame 8 has a function of setting the amount of the viscous material to be applied when the viscous material is used as the positive electrode 4. That is, this frame 8 is placed on the positive electrode current collector plate 1 in advance,
Since the coating amount becomes constant by filling the inside of the frame with the viscous substance, the thickness and size of the frame 8, that is, the surrounding area, can be determined according to the desired coating amount.

正極４に使用する活物質としては、従来よりリチウム電
池用の正極活物質として知られる種々のものを使用でき
る゛が、とくに好適なものとしてＴｉＳ２、ＭｏＳ２、
Ｖ６Ｏ１３、ｖ２０５、ｖＳｅ２、Ｎ　ｉ　ＰＳ３が挙
げられ、これらは２種以上を併用してもよい。As the active material used for the positive electrode 4, various materials conventionally known as positive electrode active materials for lithium batteries can be used, but particularly suitable ones include TiS2, MoS2,
Examples include V6O13, v205, vSe2, and N i PS3, and two or more of these may be used in combination.

さらに、負極６としてはリチウムおよびリチウム合金の
いずれも使用可能であるが、リチウム単独では長期の間
に電解質と反応する可能性があるため、アルミニウムな
どとの合金化を図ることが望ましい。Furthermore, both lithium and lithium alloys can be used as the negative electrode 6, but since lithium alone may react with the electrolyte over a long period of time, it is desirable to alloy it with aluminum or the like.

以上の如く構成されるこの発明のリチウム電池は、電解
質として特定の粘性体を用いることによる既述した電池
組立て上の利点のほか、後記実施例と比較例の電池特性
の比較において明確に示されるように二次電池としての
寿命が通常の液体電解質を用いたものに比べて飛躍的に
増大するという重要な特徴点を備えている。この理由に
ついては明確ではないが、ある程度の充放電を繰り返し
たのちに電池を分解して詳細に観察すると、通常の液体
電解質を用いた電池では負極からセパレータを貫通して
正極内部に達するリチウムのデンドライト状析出物が顕
著に認められるのに対して、この発明の電池では上記デ
ンドライト状析出物がほとんど認められない。従ってこ
の発明の電池では電解質中のゲル成分が電着したリチウ
ム面の特異的活性点を殺すように作用し、充放電におけ
るリチウムの溶解析出が負極全面に均一平滑的に行われ
る結果、デンドライト状析出物に起因する短絡が防止さ
れるものと推測される。The lithium battery of the present invention constructed as described above has the above-mentioned advantages in terms of battery assembly due to the use of a specific viscous material as an electrolyte, as well as the advantages clearly shown in the comparison of battery characteristics between Examples and Comparative Examples described later. As such, it has the important feature that the lifespan of a secondary battery is dramatically increased compared to those using a normal liquid electrolyte. The reason for this is not clear, but when the battery is disassembled and observed in detail after a certain amount of charging and discharging, it is found that in batteries using a normal liquid electrolyte, lithium reaches from the negative electrode through the separator to the inside of the positive electrode. While dendrite-like precipitates are clearly observed, in the battery of the present invention, the above-mentioned dendrite-like precipitates are hardly observed. Therefore, in the battery of this invention, the gel component in the electrolyte acts to kill the specific active sites on the electrodeposited lithium surface, and as a result, the dissolution and deposition of lithium during charging and discharging occurs uniformly and smoothly over the entire surface of the negative electrode, resulting in a dendrite-like structure. It is presumed that short circuits caused by precipitates are prevented.

なお、この発明の電池における両極集電板は、第１図で
示すようにその一方を皿形とする以外に；両方を共に皿
形としたり、あるいは両方を共に平板状として周辺部間
にセラミック製などのスペーサを介在させた構造として
もよい。このスペーサを用いる場合はその両面と両極集
電板との間をそれぞれ接着封止することは言うまでもな
い。また電池外形は方形以外の多角形および円形など、
用途に応じた種々の形状とすることができる。さらに電
池の総厚はとくに限定されないが、１．　Ｏｔｍ厚以下
、好ましくは０．３〜０．７＃厚程度においてこの発明
の適用効果が大きい。In addition, in the battery of the present invention, in addition to having one of the current collector plates in the shape of a plate as shown in FIG. It is also possible to have a structure in which a spacer, such as a product made of aluminum or the like, is interposed. When using this spacer, it goes without saying that both surfaces of the spacer and the bipolar current collector plates must be adhesively sealed. In addition, the external shape of the battery may be polygonal or circular other than rectangular.
It can be made into various shapes depending on the purpose. Further, the total thickness of the battery is not particularly limited, but 1. The application effect of the present invention is large when the thickness is less than Otm, preferably about 0.3 to 0.7#.

〔発明の効果］ この発明の薄型リチウム電池は、電解質が特定の成分か
らなる粘性体であるため、電池組立時に従来の液体電解
質のように外部へ流出する惧れがなく、その必要量を塗
り付けなどの簡単な操作によって電池内の所定領域全体
に均一に添加でき、その添加量も広範囲で調整可能であ
り、接着剤による確実な封止を行うことができ、加えて
電解質が非流動性であるためにこれが封止部に接触する
のを防止できるので漏液を生じにくく、薄型電池として
の適性に優れる。またこの電池では、上記封止に用いる
接着剤として取扱いおよび封止操作が容易なシート状な
どに成形した熱融着性材料を使用しても、その融着時の
加熱にて電解質が飛散することはなく、充分な封止が可
能である。さらにこの電池では充放電における負極リチ
ウムの可逆性が理想的に維持されることから、二次電池
として極めて長寿命である。[Effects of the Invention] In the thin lithium battery of the present invention, since the electrolyte is a viscous body made of specific components, there is no risk of it leaking out like conventional liquid electrolytes when assembling the battery, and the necessary amount can be applied. It can be added uniformly to the entire predetermined area within the battery by simple operations such as attaching the adhesive, and the amount added can be adjusted over a wide range, allowing reliable sealing with adhesive.In addition, the electrolyte is non-fluid. Since this can be prevented from coming into contact with the sealing portion, leakage is unlikely to occur, making it excellent in suitability as a thin battery. Furthermore, in this battery, even if a heat-fusible material formed into a sheet shape that is easy to handle and seal is used as the adhesive for sealing, the electrolyte will scatter due to the heating during the welding process. There is no problem, and sufficient sealing is possible. Furthermore, since this battery ideally maintains the reversibility of the negative electrode lithium during charging and discharging, it has an extremely long life as a secondary battery.

〔実施例〕〔Example〕

以下、この発明の実施例を比較例と対比して説明する。 Examples of the present invention will be described below in comparison with comparative examples.

実施例Ｉ ＬｉＢφ４のジメトキシエ゛タン付加物（ＬｉＢφ４ニ
ジメトキシエタンのモル比１　：　３　）２２．０’ヲ
γ−ブチロラクトン４０ｍｅに溶解し、これに平均分子
量７，０００のポリ（３−ビニル−１・４−ブチロラク
トン）１）．８６ｙを添加混合して密封し、１２０℃で
１時間加熱して均一な粘性体からなる電解質を得た。こ
の電解質の２５°Ｃにおけるイオン伝導度はｌＸＩＯ３
／ｃＩｎであった。Example I LiBφ4 dimethoxyethane adduct (LiBφ4 dimethoxyethane molar ratio 1:3) was dissolved in 40me of γ-butyrolactone, and poly(3-vinyl-1 with an average molecular weight of 7,000)・4-Butyrolactone) 1). 86y was added and mixed, the mixture was sealed, and heated at 120° C. for 1 hour to obtain an electrolyte consisting of a uniform viscous body. The ionic conductivity of this electrolyte at 25°C is lXIO3
/cIn.

次に、この電解質とＴｉＳ２粉末とを体積比３０ニア０
で混練し、この混練物をスクリーン印刷法により一辺１
５＋ｕ＋の正方形で厚さ０．１　ｍｍのステンレス製平
板からなる正極集電板の表面に、その上に載置したポリ
プロピレン製の方形の枠体の内側に一杯になるように塗
布し、−辺１０ｒｔｔｍの正方形で厚さ０．１　ｒｒｒ
ｍの正極を形成した。この正極上に厚さ２５／”の多孔
性ポリプロピレンからなるセパレータ（ポリプラスチッ
ク社製の商品名ジュラガード２４００）に凹凸形状を形
成して、上記電解質を予め塗り付けて全体に均一に含浸
させたものを積層し、さらにこのセパレータ上にリチウ
ム−アルミニウム合金製で一辺４闘の正方形筒からなる
厚さ８０戸の負極を積層した。Next, this electrolyte and TiS2 powder were mixed at a volume ratio of 30 near 0.
This kneaded material is then screen printed on one side.
Apply it to the surface of a positive electrode current collector plate made of a stainless steel flat plate with a square shape of 5+u+ and a thickness of 0.1 mm, so that it fills the inside of a rectangular frame made of polypropylene placed on top of the positive electrode current collector plate, and then 10rttm square with thickness 0.1 rrr
A positive electrode of m was formed. On this positive electrode, a separator made of porous polypropylene with a thickness of 25 mm (product name: Duraguard 2400, manufactured by Polyplastics) was formed with an uneven shape, and the above electrolyte was applied in advance to uniformly impregnate the entire surface. Further, on top of this separator, a negative electrode made of lithium-aluminum alloy and having a thickness of 80 mm and consisting of a square tube with 4 sides on each side was laminated.

次に、正極集電板の周辺部上に厚さ５０戸２幅２　ｍｍ
の方形環状シートからなる変性ポリオレフィン系ホット
メルト接着剤が載置された状態で、−辺１５ｍｍの正方
形で厚さ０．１　ｒｕｍの皿形ステンレス製板からなる
負極集電板を被冠し、両極集電板の周辺部を圧接下で１
８０°Ｃに加熱して熱融着封止し、第１図で示す構造の
電池総厚０．５　ｍｍの薄型リチウム電池を作製した。Next, on the peripheral part of the positive electrode current collector plate, a thickness of 50 mm and a width of 2 mm is applied.
A modified polyolefin hot melt adhesive made of a rectangular annular sheet was placed thereon, and a negative electrode current collector plate made of a dish-shaped stainless steel plate with a square side of 15 mm and a thickness of 0.1 rum was placed on top. 1 under pressure contact around the periphery of the bipolar current collector plate.
The product was heated to 80° C. and sealed by heat sealing to produce a thin lithium battery having a total battery thickness of 0.5 mm and having the structure shown in FIG.

なお、この電池作製過程において、セパレータに含浸し
た電解質の周辺部への流れ出しは全く認められず、また
熱融着時に電解質の飛散を生じず確実な封止状態が達成
された。In the process of manufacturing this battery, no leakage of the electrolyte impregnated into the separator to the surrounding area was observed, and a reliable sealing state was achieved without scattering of the electrolyte during heat fusion.

実施例２ ポリ（３−ビニル−１・４−ブチロラクトン）に代えて
平均分子量６，０００のポリ（４−ビニル−１・４−ブ
チロラクトン）７５ｙを使用すると共にγ−ブチロラク
トンに代えてプロピレンカーボネート４０ｍｅを用いた
以外は、実施例１と同様にして均一な粘性体からなる電
解質を得た。この電解質の２５°Ｃにおけるイオン伝導
度は５’Ｘ１０　　Ｓ／ｃｍであった。次にこの電解質
を用いて実施例１と同様にして電池総厚０，５朋の薄型
リチウム電池を作製した。Example 2 Poly(4-vinyl-1,4-butyrolactone) 75y having an average molecular weight of 6,000 was used in place of poly(3-vinyl-1,4-butyrolactone), and propylene carbonate 40me was used in place of γ-butyrolactone. An electrolyte made of a uniform viscous body was obtained in the same manner as in Example 1 except that . The ionic conductivity of this electrolyte at 25°C was 5'X10 S/cm. Next, using this electrolyte, a thin lithium battery having a total battery thickness of 0.5 mm was produced in the same manner as in Example 1.

実施例３ ポリ（３−ビニル−１・４−ブチロラクトン）に代えて
３−ビニル−１・４−ブチロラクトンとアクリロニトリ
ルとのモノマーモル比７０°：３０の共重合体（平均分
子量１０，０００　）１８．３ｙを使用した以外は、実
施例１と同様にして均一な粘性体からなる電解質を得た
。この電解質の２５°Ｃにおけるイオン伝導度は０．５
　Ｘ　１０　　Ｓ／ｃｍであった。Example 3 Poly(3-vinyl-1,4-butyrolactone) was replaced with a copolymer of 3-vinyl-1,4-butyrolactone and acrylonitrile in a monomer molar ratio of 70°:30 (average molecular weight 10,000)18. An electrolyte made of a uniform viscous body was obtained in the same manner as in Example 1 except that 3y was used. The ionic conductivity of this electrolyte at 25°C is 0.5
X 10 S/cm.

次にこの電解質を用いて実施例１と同様にして電池総厚
０．５朋の薄型リチウム電池を作製した。Next, using this electrolyte, a thin lithium battery having a total battery thickness of 0.5 mm was produced in the same manner as in Example 1.

実施例４ ポリ（３−ビニル−１・４−ブチロラクトン）に代えて
３−ビニル−１・４−ブチロラクトンとメチルメタクリ
レートとのモノマーモル比５０：５０の共重合体（平均
分子量２０，０００）１）．０ｙを使用した以外は、実
施例１と同様にして均一な粘性体からなる電解質を得た
。この電解質の２５°Ｃにおけるイオン伝導度は１．５
Ｘ１０　　Ｓ／ｃｍであった。次にこの電解質を用いて
実施例１と同様にして電池総厚０．５間の薄型リチウム
電池を作製した。Example 4 Copolymer of 3-vinyl-1,4-butyrolactone and methyl methacrylate at a monomer molar ratio of 50:50 (average molecular weight 20,000) 1) in place of poly(3-vinyl-1,4-butyrolactone) ．． An electrolyte made of a uniform viscous body was obtained in the same manner as in Example 1 except that Oy was used. The ionic conductivity of this electrolyte at 25°C is 1.5
It was X10 S/cm. Next, using this electrolyte, a thin lithium battery with a total battery thickness of 0.5 mm was produced in the same manner as in Example 1.

なお、実施例２〜４における電池作製過程においても、
実施例１の場合と同様にセパレータに含浸した電解質の
周辺部への流れ出しは全く認められず、また熱融着時に
電解質の飛散を生じず確実な封止が達成された。In addition, also in the battery manufacturing process in Examples 2 to 4,
As in the case of Example 1, no flow of the electrolyte impregnated into the separator to the peripheral area was observed, and reliable sealing was achieved without scattering of the electrolyte during thermal fusion.

比較例 ＴｉＳ粉末とテフロン粉末の重世比１００：５の混合物
を加圧成形して一辺１０朋、厚さ０．１　ｍｍの正方形
板状正極を作製し、これを実施例１と同様の正極集電板
上に載置した。次にＬｉＢφ４のジメトキシエタン付加
物（実施例１と同じ）１）．２部をプロピレンカーボネ
ート２３．７８部に溶解して液体電解質を調製し、この
電解質を上記正極上に滴下したのち、正極上に電解質を
含浸していない実施例１と同様のセパレータを積層し、
このセパレータ上に上記電解質を添加した上で、実施例
１と同様の負極を積層した。次に正極集電板の周辺部に
エポキシ系接着剤が塗布された状態で、実施例１と同様
の負極集電板を被冠して上記接着剤の硬化による封止を
行って電池総厚０．５　ｍｍのリチウム電池を作製した
。Comparative Example A square plate-shaped positive electrode with a side of 10 mm and a thickness of 0.1 mm was prepared by pressure molding a mixture of TiS powder and Teflon powder in a weight ratio of 100:5. It was placed on a current collector plate. Next, LiBφ4 dimethoxyethane adduct (same as Example 1) 1). 2 parts were dissolved in 23.78 parts of propylene carbonate to prepare a liquid electrolyte, and this electrolyte was dropped onto the positive electrode, and then a separator similar to Example 1 which was not impregnated with electrolyte was laminated on the positive electrode,
The above electrolyte was added onto this separator, and then the same negative electrode as in Example 1 was laminated. Next, with an epoxy adhesive applied to the periphery of the positive electrode current collector plate, a negative electrode current collector plate similar to that in Example 1 is covered, and the adhesive is cured to seal the battery. A 0.5 mm lithium battery was fabricated.

なお、この電池作製過程においては、２回にわたる電解
質の滴下を非常に注意深く行ったにもかかわらず、電解
質の電池周辺側への流出による不良品が高率で発生した
。またエポキシ系接着剤の塗布操作は容易でなかった。In this battery manufacturing process, even though the electrolyte was very carefully dropped twice, a high rate of defective products occurred due to the electrolyte flowing out to the periphery of the battery. Moreover, the operation of applying the epoxy adhesive was not easy.

上記の実施例１〜４および比較例にて得られた薄型リチ
ウム電池について二次電池として２５°Ｃの温度下で３
０μＡの定電流による充放電サイクル特性を充電終止電
圧２，７Ｖ、放電終止電圧１．５■として測定した。こ
の結果を第２図で示す。なお図中の曲線Ａ１は実施例１
、Ａ２は実施例２、Ａ３は実施例３、Ａ４は実施例４、
Ｂは比較例にそれぞれ対応している。The thin lithium batteries obtained in Examples 1 to 4 and Comparative Examples above were tested as secondary batteries at a temperature of 25°C.
The charge/discharge cycle characteristics at a constant current of 0 μA were measured at a charge end voltage of 2.7 V and a discharge end voltage of 1.5 μ. The results are shown in FIG. Note that the curve A1 in the figure is for Example 1.
, A2 is Example 2, A3 is Example 3, A4 is Example 4,
B corresponds to each comparative example.

この第２図の結果から明らかなように、通常の液体電解
質を用いた電池では充放電の繰り返しによる放電容量の
低下が著しく、二次電池としての寿命艙短いのに対して
、特定の粘性体からなる電解質を使用したこの発明に係
る電池では充放電の繰り返しによる放電容量の低下が極
めて僅かであって二次電池として理想的な長寿命である
ことが判るＯ 一方、前記実施例１で示す電解質組成においてポリ（３
−ビニル−１・４−ブチロラクトン）の添加量つまり電
解質全体に占める割合（重量％）を種々変化させた場合
の該添加量とイオン伝導度との関係を第３図に示す。ま
た該添加量の異なる電解質を用いて実施例１と同様にし
て各添加量ごとに２０個ずつのリチウム電池を作製し、
これらを６０　’Ｃにてｉケ月間保存したのち、２０に
Ω定抵抗放電を行って正極利用率を測定したところ、前
記ポリマーの各添加量ごとの正極利用率の平均値は第４
図で示すとおりであった。As is clear from the results shown in Figure 2, batteries using a normal liquid electrolyte have a significant drop in discharge capacity due to repeated charging and discharging, and have a short lifespan as a secondary battery. It can be seen that the battery according to the present invention, which uses an electrolyte consisting of O, has a very small decrease in discharge capacity due to repeated charging and discharging, and has a long life that is ideal as a secondary battery. In the electrolyte composition, poly(3
FIG. 3 shows the relationship between the amount of addition (vinyl-1,4-butyrolactone), that is, the proportion (% by weight) of the electrolyte in the total electrolyte, and the ionic conductivity. In addition, 20 lithium batteries were produced for each addition amount in the same manner as in Example 1 using electrolytes with different addition amounts,
After storing these at 60'C for i months, the positive electrode utilization rate was measured by performing Ω constant resistance discharge on 20 days.The average value of the positive electrode utilization rate for each added amount of the polymer was 4
It was as shown in the figure.

第３図の結果から、ラクトン構造を有するポリマーの添
加量が多くなるほど電解質のイオン伝導度が低下する傾
向があり、良好なイオン伝導度を得るには該添加量を４
０重量％以下とすることが望ましいと言える。また第４
図の結果から、上記ポリマーの添加量が少なすぎると電
解質の流動性が大きくなって封止部分の信頼性が低下し
て正極利用率が悪く、逆に添加量が多すぎても正極利用
率が悪くなり、正極利用率を４０％以上とするには該添
加量を４０重量％以下、同５０％以上とするには３０重
量％以下とすればよいことが判る。From the results shown in Figure 3, the ionic conductivity of the electrolyte tends to decrease as the amount of polymer with a lactone structure increases, and to obtain good ionic conductivity, the amount added is 4.
It can be said that it is desirable that the content be 0% by weight or less. Also the fourth
From the results shown in the figure, if the amount of the polymer added is too small, the fluidity of the electrolyte increases and the reliability of the sealing part decreases, resulting in a poor cathode utilization rate, whereas if the amount added is too large, the cathode utilization rate is poor. It can be seen that to increase the positive electrode utilization rate to 40% or more, the amount added should be 40% by weight or less, and to increase the positive electrode utilization rate to 50% or more, it should be 30% by weight or less.

ただし該添加量の下限は非流動性となる４重量％程度で
ある。However, the lower limit of the amount added is about 4% by weight, which results in non-flowability.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図はこの発明に係る薄型リチウム電池の一例におけ
る縦断面図、第２図はこの発明の実施例および比較例で
得られた電池の充放電サイクル特性図、第３図はこの発
明の電池に用いる電解質の分子内にラクトン構造を有す
るポリマーの添加量とイオン伝導度との関係を示す特性
図、第４図は同添加量と正極利用率との関係を示す特性
図である。 １・・・正極集電板、１ａ・・・周辺部、２・・・負極
集電板、２ａ・・・周辺部、３・・・接着剤層、４・・
・正極、６・・・負極、７・・・セパレータ 特許出願人　　日立マクセル株式会社 第１ｍ 第２図 ブイ７１Ｌ数 第３図FIG. 1 is a longitudinal cross-sectional view of an example of a thin lithium battery according to the present invention, FIG. 2 is a charge-discharge cycle characteristic diagram of batteries obtained in Examples and Comparative Examples of the present invention, and FIG. 3 is a battery of the present invention. FIG. 4 is a characteristic diagram showing the relationship between the added amount of a polymer having a lactone structure in the molecule of the electrolyte used for this purpose and ionic conductivity, and FIG. 4 is a characteristic diagram showing the relationship between the added amount and the positive electrode utilization rate. DESCRIPTION OF SYMBOLS 1... Positive electrode current collector plate, 1a... Peripheral part, 2... Negative electrode current collector plate, 2a... Peripheral part, 3... Adhesive layer, 4...
・Positive electrode, 6...Negative electrode, 7...Separator Patent applicant Hitachi Maxell Co., Ltd. No. 1m Fig. 2 Number of buoys 71L Fig. 3

Claims (7)

【特許請求の範囲】[Claims] （１）正極集電板と負極集電板との間に正極とリチウム
またはリチウム合金からなる負極と両極間に介在するセ
パレータとを含む電池要素が配置され、上記両極集電板
の対向する平坦状の周辺部で接着封止された構造の薄型
リチウム電池において、電解質として、リチウム塩と、
分子内にラクトン構造を有するポリマーと、これら両者
を溶解する非水系溶媒とが含まれてなる粘性体が使用さ
れていることを特徴とする薄型リチウム電池。(1) A battery element including a positive electrode, a negative electrode made of lithium or a lithium alloy, and a separator interposed between the two electrodes is arranged between a positive electrode current collector plate and a negative electrode current collector plate, and a battery element is arranged between the positive electrode current collector plate and the negative electrode current collector plate, and In a thin lithium battery with a structure in which the periphery of the shape is adhesively sealed, lithium salt and lithium salt as the electrolyte are used.
A thin lithium battery characterized by using a viscous body containing a polymer having a lactone structure in its molecules and a non-aqueous solvent that dissolves both. （２）分子内にラクトン構造を有するポリマーが、分子
内にビニル基を含むラクトンの重合体である特許請求の
範囲第（１）項記載の薄型リチウム電池。(2) The thin lithium battery according to claim (1), wherein the polymer having a lactone structure in the molecule is a lactone polymer having a vinyl group in the molecule. （３）分子内にラクトン構造を有するポリマーが、分子
内にビニル基を含むラクトンとこれに共重合可能な他の
モノマーとの共重合体である特許請求の範囲第（１）項
記載の薄型リチウム電池。(3) A thin type according to claim (1), wherein the polymer having a lactone structure in the molecule is a copolymer of a lactone containing a vinyl group in the molecule and another monomer copolymerizable with the lactone. Lithium battery. （４）共重合可能な他のモノマーが（メタ）アクリロニ
トリルである特許請求の範囲第（３）項記載の薄型リチ
ウム電池。(4) The thin lithium battery according to claim (3), wherein the other copolymerizable monomer is (meth)acrylonitrile. （５）共重合可能なモノマーがメタクリル酸アルキルエ
ステルである特許請求の範囲第（３）項記載の薄型リチ
ウム電池。(5) The thin lithium battery according to claim (3), wherein the copolymerizable monomer is an alkyl methacrylate ester. （６）分子内にビニル基を含むラクトンが３−ビニル−
１・４−ブチロラクトンである特許請求の範囲第（２）
〜（５）項のいずれかに記載の薄型リチウム電池。(6) Lactone containing a vinyl group in the molecule is 3-vinyl-
Claim No. (2) which is 1,4-butyrolactone
The thin lithium battery according to any one of items (5) to (5). （７）分子内にビニル基を含むラクトンが４−ビニル−
１・４−ブチロラクトンである特許請求の範囲第（２）
〜（５）項のいずれかに記載の薄型リチウム電池。(7) Lactone containing a vinyl group in the molecule is 4-vinyl-
Claim No. (2) which is 1,4-butyrolactone
The thin lithium battery according to any one of items (5) to (5).